Last night i have updated my 6s and it is actually dead nothing working. so please dont update .
@Top Secret! such an annoying issue with iOS updates lately, if I am not wrong the same thing happened with iOS 9 too!
Anyways, if you have a iCloud of iTunes backup for the device just to a clean install from iTunes instead of OTA and it will work. Once you install iOS afresh you can restore your data from backup.